Vehicle steering pull - from product development to manufacturing

Thiago Barros Murari, Diego Morais Lima, Gilney Figueira Zebende, Marcelo Albano Moret (SENAI-CIMATEC, Ford Motor Company)

CHALLENGE - Steering pull reduction is as important as ride comfort and handling performances for driver’s safety. The objective of this study is to ensure that passengers do not have the perception that the vehicle is “pulling” to one side or the vehicle is misaligned. An aligned wheel system and robustness to the variations of terrain is investigated. The engineering attribute to be controlled is VRAT, or Vehicle Residual Aligning Torque.

SOLUTION - The proposed model simulates a compact vehicle model for five people, Macpherson suspension on the front axis and Twist Beam on the rear. VRAT is calculated as a function of several factors. Basically, the calculation factors chosen are the ones influencing the difference in forces acting on the tires of the left and right side. Cross Camber, Cross Caster and Road Crown are the specifications. The mulltibody dynamics model was developed on the MSC.ADAMS Chassis. Using a multiple regression algorithm to generate a first order polynomial, the coefficients were calculated on modeFRONTIER according to the DOE simulated in MSC Adams.

BENEFITS - The proposed method can reduce the computational cost compared to the common methods that use only a model developed in MSC.ADAMS. The proposed model obtained a reduction of 99.87% of the time to obtain all results.